Disregard please

 

I cut and pasted the above thread I had started on a different forum, but that didn't work so well. So here's the start of my thread.
Last year I did a Hemi swap into my Jeep. I used the stock radiator and fan, this worked ok, but not good enough especially when pulling my trailer. My temps were in the 220 to 230 range and once hit over 250 for a brief period of time. The 250 was when going up a steep hill while towing.
I've seen some of the radiator options and the issue I have is that my stock fan is about 1/8" or less from the water pump, so there's no room to get a bigger radiator in there, if the new one will be pushed back at all. However, I am willing to disassemble the front end and make it all fit with a new arrangement if necessary.
I do not know if I still have the original radiator or not, meaning if it's 15 years old, or if it was replaced prior to me getting the Jeep.
Any thoughts?

Thanks.

 

I used the stock 3.8 rad in my Chev 5.3 conversion and pulled a trailer up a 7% grade hill at 60mph. It warmed up a little more than normal but over the top by 200yds on the downhill it was back to normal. Do you have all the air deflectors etc in there to "guide" the air through the rad as it is important to not let any air bypass the radiator core. I run a 2018 Camaro SS fan that I swear will pull the Jeep along a level road as it pulls a lot of air. That fan is worth $500USD as it has the 3rd wire going to it for infinite speed control. Power is on it all the time regardless of ign on or off.

 

I have the factory air deflectors in place, but I am using the stock fan. I do have a winch that blocks air, but how many of us don't?
I'm familiar with the Camaro fan. Last year as I was doing the swap, I did not have the funds to put into the radiator and fan, so I went with the stock setup. This has worked OK, but not great. Now I want to eliminate the cooling issues so the radiator and/or fan will be addressed.
I was all set to get the Griffin radiator until I saw your reply. Now I'm thinking that the fan alone may just do the trick.

I spoke with a Griffin tech this morning. He said that if it was any other vehicle, he would say with confidence that a new radiator will help a lot, but he also said this doesn't apply to Jeeps because of all the other stuff that gets done to them, like winches and lights, etc.
Then I mention that what if I up in an air dam to try and catch more air and divert it to the radiator. He cited the example of many OEM cars that are doing this already.
I just looked under my Jeep and looks like an air dam is do-able, if mounted just behind the sway bar bracket.

I'll start with the fan then if necessary, new radiator as well. But the lower air dam is going in no matter what.

Thanks again.

 

Is the stock fan getting up to high speed? You can take it for a rip where you know it does overheat with a jumper to make the fan run on high speed. I would find the circuit that switches the hi-speed relay and run a hot to the coil. See what happens.

 

Interesting.
I did not know it was a 2 speed fan. It comes on, that's all I can say. I've let this Jeep sit for the last 6 months or so while I worked on a 1958 CJ5. It's time for the Moab trip so I'm working on the JK again.
I will look into to the fan. I can say that I've had the high speed function go out on me in my Mustang and it was an immediate and obvious difference.
The JK cools just well enough to be marginally acceptable, but it needs attention.
Thanks.

 

After speaking with Todd at jeep speed shop this morning, I bought the Camaro fan. Todd said the Camaro fan is way better than the Jeep one and a '08 (the one I have) is the worst.
Question though is why is an external fan controller needed for the GM fan. Looks like the Jeep has a high and low speed, so why can't this be spliced to the GM fan.

 

Does the fan have 3 wires to it or 2?

 

I don't know what the fan has, it'll on its way now. I was also thinking that why not just use the JK wires to run that fan.

But as usual I spoke with Todd at JSS. He said that direct wiring will not work because the Camaro has, a "pulse " fan. No idea about the science behind that, but the gist of it is that I will need a fan controller.

 

If he is referring to a pulse fan he is mentioning what is PWM which stands for Pulse Width Modulated. If that is the case then it is likely it will have 3 wires. 2 are for power with a 60A fused supply direct from the battery and the 3rd wire is a small control wire that reeives a pulse width signal to indicate speed and to turn on. Therefore the controller gets a temperature signal from the Jeep side that sends that requirment for on/off and speed to the fan. How it treats the AC system on fan signal I am not sure but normally that signal to the fan is controlled by AC system pressure. The JK wires have to be at least 60A rating then you can use them. But they are switched and as per above, if it is a 3 wire system, you need unswitched supply side diverted to the fan. Have to wait to see if the fan is 2 wire or 3.